The COVID-19 pandemic has been monitored by applying different strategies, including SARS-CoV-2 detection with clinical testing or through wastewater-based epidemiology (WBE). We used the latter approach to follow SARS-CoV-2 dispersion in Tapachula city, located in Mexico’s tropical southern border region. Tapachula is a dynamic entry point for people seeking asylum in Mexico or traveling to the USA. Clinical testing facilities for SARS-CoV-2 monitoring are limited in the city. A total of eighty water samples were collected from urban and suburban rivers and sewage and a wastewater treatment plant over 4 months in Tapachula. We concentrated viral particles with a PEG-8000-based method, performed RNA extraction, and detected SARS-CoV-2 particles through RT-PCR. We considered the pepper mild mottle virus as a fecal water pollution biomarker and analytical control. SARS-CoV-2 viral loads (N1 and N2 markers) were quantified and correlated with official regional statistics of COVID-19 bed occupancy and confirmed cases (r > 91%). Our results concluded that WBE proved a valuable tool for tracing and tracking the COVID-19 pandemic in tropical countries with similar water temperatures (21–29 °C). Monitoring SARS-CoV-2 through urban and suburban river water sampling would be helpful in places lacking a wastewater treatment plant or water bodies with sewage discharges.

COVID-19 大流行已通过应用不同的策略进行监测，包括通过临床测试或通过基于废水的流行病学 (WBE) 检测 SARS-CoV-2。我们使用后一种方法来跟踪位于墨西哥热带南部边境地区的塔帕丘拉市的 SARS-CoV-2 扩散情况。Tapachula 是在墨西哥寻求庇护或前往美国的人们的动态切入点。该市用于监测 SARS-CoV-2 的临床检测设施有限。在塔帕丘拉的四个月内，从城市和郊区河流以及污水和污水处理厂共收集了 80 份水样。我们使用基于 PEG-8000 的方法浓缩病毒颗粒，进行 RNA 提取，并通过 RT-PCR 检测 SARS-CoV-2 颗粒。我们将辣椒轻度斑驳病毒视为粪便水污染生物标志物和分析对照。对 SARS-CoV-2 病毒载量（N1 和 N2 标记）进行量化，并与 COVID-19 床位占用和确诊病例的官方区域统计数据相关联（r  > 91%）。我们的结果得出结论，WBE 被证明是在水温相似（21-29 °C）的热带国家追踪和追踪 COVID-19 大流行的宝贵工具。通过城市和郊区河水采样监测 SARS-CoV-2 将有助于缺乏污水处理厂或有污水排放的水体的地方。